The present invention relates to hydrodemetalation and hydrodesulfurization and to catalysts useful for simultaneously carrying out hydrodemetalation and hydrodesulfurization of a heavy oil feedstock. The invention relates to catalyst of certain pore characteristics, especially macroporosity characteristics, which have been found to be surprisingly effective in simultaneous hydrodesulfurization and hydrodemetalation of heavy oils.
U.S. Pat. No. 3,898,155 discloses a process for simultaneous demetalation and desulfurization of heavy oils containing at least 50 ppm metals under hydrogenation conditions using a catalyst composition comprising a Group VI metal and at least one Group VIII metal composited with a refractory oxide. The catalyst has 10 to 40 percent of its pore volume in macropores and from 60 to 90 percent of its pore volume in micropores, at least 80 percent of the micropore volume being in pores having a diameter of at least 100 A units, said catalyst composition further having a total pore volume of at least 0.5 ml per gram, an average pore diameter greater than 100 A units, and a surface area of at least 100 square meters per gram.
Taiwanese Patent No. NI 23,976, issued Apr. 16, 1986, discloses a process for demetalation and desulfurization of asphalt containing hydrocarbons under hydrogenation conditions employing a catalyst comprising molybdenum, at least one Group VIII metal, and alumina, the catalyst having a total pore volume based upon measurements by mercury penetration of at least 0.4 cc per gram, a macropore volume in the range of 5-50% of catalyst pore volume, and a mesopore volume of at least 0.12 cc per cc of catalyst volume.
U.S. Pat. No. 4,008,149 discloses a catalyst for use in hydrodesulfurization, hydrodemetalation and hydrodenitrification. The catalyst has a 250 to 300-m.sup.2 /g surface area, at least 80 percent of the pore volume in the range 0 to 150 .ANG., is from pores from 60 to 150 .ANG.; less than 0.01 milliliters per gram of pore volume is from pores in the range 150 to 2000 .ANG.; and the volume of the pores in the range 0 to 600 .ANG. is between about 0.45 and 0.60 milliliters per gram of catalyst.
U.S. Pat. No. 4,301,037 discloses a bimodal alumina catalyst support having most of the surface area in a micropore region having pores of less than 500 .ANG., and also having a macropore region having pores with diameters of 1000 .ANG. to 10,000 .ANG..
U.S. Pat. No. 4,225,421 discloses a bimodal catalyst for use in hydrodemetalation and hydrodesulfurization of a hydrocarbon feedstock containing asphaltenes and metals. The catalyst contains one active hydrogenation metal selected from Group VIB deposited on a support comprising alumina. The catalyst has a surface area within the range of about 140 to about 300 m.sup.2 /g, a total pore volume based upon measurement by mercury penetration within the range of about 0.4 cc/g to about 1.0 cc/g, and comprising about 60% to about 95% of its micropore volume in micropores having diameters within the range of about 50 .ANG. to about 200 .ANG., 0% to about 15% of its micropore volume in pores having diameters within the range of about 200 .ANG. to about 600 .ANG. and about 3% to about 30% of said total pore volume based upon measurements by mercury penetration in macropores having diameters of 600 .ANG. or greater.
U.S. Pat. No. 4,454,026 discloses a hydrotreating catalyst comprising a hydrogenating component and a support comprising at least one porous refractory inorganic oxide, the catalyst having a BET surface area of 150 to about 190 m.sup.2 /g, bulk density of at least about 0.2 grams per cc, total pore volume of at least about 0.9 cc/g with mercury penetration pore volume of at least about 0.1 cc/g and macropores with radii of 600 to 25,000 .ANG., such surface area, pore size distribution and total pore volume being effective to give an average pore diameter of at least 230 .ANG., calculated as 4 times the pore volume over the surface area.